APA (7th ed.) Citation

Darwin, C. (1986). The different forms of flowers on plants of the same species. University of Chicago Press.

Chicago Style (17th ed.) Citation

Darwin, Charles. The Different Forms of Flowers on Plants of the Same Species. Chicago: University of Chicago Press, 1986.

MLA (9th ed.) Citation

Darwin, Charles. The Different Forms of Flowers on Plants of the Same Species. University of Chicago Press, 1986.